Receiver could delete picture ASAP, and discourage behavior. If they keep, spread, or encourage they're complicit. Of course, there's a difference in severity between 1 nude of 1 person, or a myriad, or being an adult with a myriad.
Sender getting prosecuted for spreading their own nude as minor might be weird, but also makes sense. Its not as if they'd be a registered sex offender as a minor.
Put this way: what if it was an illegal firearm? We can't just turn a blind eye to youth breaking law, but we can't treat them like adults either. There's a solid middle ground: hold parents accountable till teenager, then both, and at age 16 the teenager but not with fully implemented adult law. Interestingly, that's approx how countries deal with it, or variants of that at least.
TL;DR if properly nuanced, we can deal with issues like these, though we may disagree on these nuances, I'm quite sure we'll agree on the outliers.
I think the Australian state of Victoria gets it more or less right – section 51M of the Crimes Act 1958 [0] makes it explicitly legal for children to produce, possess or distribute images of themselves. Adults (and in some cases other children) can still be prosecuted if they encourage/entice/assist/etc the child to do it, but the child themselves commits no crime.
> Its not as if they'd be a registered sex offender as a minor.
A number of American states do in fact put minors on the sex offender registry. For example, [1] describes how a woman was registered as a sex offender in Michigan after being convicted of "criminal sexual conduct" as a 10 year old
> Put this way: what if it was an illegal firearm?
A fifteen year old who takes a picture of themselves naked, the primary risk of harm is to themselves, and the harm they are risking is psychosocial rather than physical. By contrast, a fifteen year old with an illegal firearm easily poses a risk of death or serious physical injury, not just to themselves, but also to others. Hence, criminally prosecuting the later is far easier to morally justify than criminally prosecuting the former. The situations aren't really comparable.
> We can't just turn a blind eye to youth breaking law
Well, like Victoria has done, the law can be changed so that they aren't breaking it.
[0] http://classic.austlii.edu.au/au/legis/vic/consol_act/ca1958...
[1] https://www.newyorker.com/magazine/2016/03/14/when-kids-are-...
I don't think you realize just how common this is. There are very few people managing high school and college machine shops who haven't helped cover up an NFA violation. Even outside that making oil filter silencers for .22 rifles (or other cheap guns high schoolers have access to) is not at all uncommon. Eventually most grow out of it (i.e. they have a real life and the risk reward calculus changes).
Likewise teenagers routinely get exposed to hard drugs and "the system" is the last thing that helps that.
Damn near every adult has a bunch of "I'd be in prison if the caught me" stories from high school.
So yeah, I think we should handle both with a stern talking too about federal prison and not much else. Most kids will mature out of this behavior and it's not worth risking screwing all of them to try and pre-emptively save the few that won't grow out of it.
(I do think 14 year olds should be discouraged from taking and sending nude pictures of themselves – it is the sort of thing they could easily come to regret in a few more years – but I don't think criminal prosecution is an ethical way of providing that discouragement.)